Optical dating techniques
Artifacts which can be dated using these methods include ceramics, burned lithics, burned bricks and soil from hearths (TL), and unburned stone surfaces that were exposed to light and then buried (OSL). Geologists have used OSL and TL to establish long, log chronologies of landscapes; luminescence dating is a powerful tool to help date sentiments dated to the Quaternary and much earlier periods. The potential of using thermoluminescence to date buried soils developed on colluvial and fluvial sediments from Utah and Colorado, U. Minerals, in fact, everything in our planet, are exposed to cosmic radiation: luminescence dating takes advantage of the fact that certain minerals both collect and release energy from that radiation under specific conditions.Crystalline rock types and soils collect energy from the radioactive decay of cosmic uranium, thorium, and potassium-40.An outline of the general physical principles of luminescence dating is given.A case study of fluvial sands from the lower terrace of the Moselle valley is then presented to describe the range of field and laboratory procedures required for successful luminescence dating.Absolute dating methods have been developed over the last five decades (Jull and Scott, 2007).They are now largely used to date not only palaeontological or organic remains, but also minerals that characterise detrital clastic sedimentary material.
The intensity of blue, green or infrared light that is created when an object is stimulated is proportional to the number of electrons stored in the mineral's structure and, in turn, those light units are converted to dose units.Materials of geological origin will have absorbed considerable quantities of radiation since their formation, so any human-caused exposure to heat or light will reset the luminescence clock considerably more recently than that since only the energy stored since the event will be recorded.The way you measure energy stored in an object that you expect has been exposed to heat or light in the past is to stimulate that object again and measure the amount of energy released.The exposure to radioactive elements continues, and the minerals begin again storing free electrons in their structures.If you can measure the rate of acquisition of the stored energy, you can figure out how long it has been since the exposure happened.